Nature Notes: Battle of the Grasses

If you take a ride out to Montauk via the parkway, you will pass through Hither Woods. As you motor along, keep your eyes on the rusting guardrails. Just behind them you will find a very healthy four-foot-high hedge of big bluestem grass, one of the original staples of old Montauk’s bountiful prairie. At one time it stretched from the western end of the Napeague isthmus to the point, a few trees here and there, but mostly grasses and wildflowers.
Prairies remain so under the influence of the elements, in particular strong winds and sparse rainfall. But fire, either intentionally set or caused by lightning strikes, also plays a big part in maintaining grasslands. Montauk and other parts of Long Island have been burnt over since pre-Columbian times. New Long Island townships, forming close on the heels of settlement by the Dutch and English in the early 1600s, enacted laws limiting Indian burns. But even so, Montauk remained wild right up into the 1950s. Burns kept the grasslands in good stead for grazing. It wasn’t until 1900 that Hither Woods began to sprout as many trees as grasses and forbs. Most of Montauk east of Fort Pond was prairie — now called “maritime grasslands” — until well after the end of World War II.
The state’s Montauk Downs Golf Course wasn’t carved out of the woods but out of pre-existing grasslands. Culloden Point was mostly grasslands. The lands north of the golf course, now as wooded as not and almost completely residential, were covered with big bluestem, Indian nut grass, switch grass, little bluestem, ladies’-tresses orchids, bushy frostweed, bearberry, gray goldenrod, bird’s-foot violets, and sand-plain gerardia to mention just a few of the many typical prairie plants that grew there. Norman Taylor, who published a monograph on Montauk’s vegetation in the 1920s, noted that in late August one could look east from the Montauk Inn and see the then houseless moorlands carpeted with the pink-purple flowers of the sand-plain gerardia as far as the eye could see. Today, the sand-plain gerardia, Agalinis acuta, is listed as federally endangered and is found in only a handful of places on Long Island and in New England. To do well it needs to be regularly grazed or burnt over.
Today, Montauk’s grasslands are limited to the highlands and lowlands east of Lake Montauk, and despite grazing by livestock and the efforts of the Nature Conservancy to keep them in prairie via proscribed burns, they are growing up into a shrubby savannah infiltrated by many different non-native weedy species. Long Island’s other major prairie, the Hempstead Plains, famous for fostering the beginnings of American aviation, has been reduced to about 17 acres. This little plot is closely watched over and has several of the species found in Montauk’s remaining grassland acres.
Perennial grasses of many species belonging to many different genera are the mainstays of prairies and maritime grasslands. They produce a thickish turf that tends to inhibit the growth of woodies, while at the same time, providing numerous cracks and crannies in which goldenrods, gerardias, and grass-like orchids thrive. In the presence of livestock, any shrub or tree seedling is quickly gobbled up, or, if some survive predation, a summer drought will come along and do them in.
We still have the bluestems and the other native grasses today; their genes go back to when Amerindians were the only humans on Long Island, almost to the end of the ice age. They are persistent, and in most cases, limited in their local distribution to the sides of roads or old fields.
Ironically, two grasses from afar, Eurasian phragmites and Asian bamboo, are becoming as common as our native grasses. They are two of the tallest grasses — phragmites reaches 12 to 15 feet at times but is dwarfed by bamboos that can grow as tall as 50 feet. Like most of our native grasses, they are perennial, but unlike our native grasses, they tend to be very selfish, forming exclusive monoclonal stands that keep out all other plant species.
Their success here is largely dependent on their mode of reproduction. They can produce flowers, but they choose to copy themselves vegetatively. They send out underground stems, or rhizomes, which can travel 100 feet or more, sprouting up new shoots every couple of feet or so. These rhizomes cross and recross onse another weaving a sturdy underground tapestry that sucks up all the available water and nutrients to the detriment of would-be competitors. It takes just a single phragmites or bamboo to produce a colony, all with the exact same genetics, all clones of the parent.
No need for cross-pollination to keep up with competitors; they are so good at what they do, they don’t need to be different. The more identical they are, the better they do. Bamboo rhizomes can go through wood, plastic, even some metals. Pragmites rhizomes are piercing to a degree, but not as successfully so as bamboo ones. It’s hard for phragmites rhizomes to pass under a road where the soils are under heavy compression. The thriving phragmites stand on the south side of Bluff Road where it issues from Indian Wells Highway in Amagansett has been studying the wetland 20 feet away on the north side of the road, which is phragmites free, for years and years and doesn’t quite know how to get there. It would be an easy cross for bamboo rhizomes.
Rhizomes not only extend out, spreading the colony centrifugally, but like tree trunks and other plant stems, they convey nutrients and water over considerable distances. Thus phragmites, which is a fresh water-loving plant, can grow in areas deluged by salt water because the rhizomes carry the fresh water from an upland source out onto the salt marsh. Sever the connection and the salt-marsh phragmites perishes.
Yes, there’s a pitched battle of the grasses going on throughout Long Island and right here under our noses on the South Fork, as well. The giant foreigners seem to be winning, the natives losing out.